[test] sharing types between import and export (#1328)

* sharing types between import and export

* also test variant compatibility

* Rust test

Author: cpetig

tests/runtime/common-types/compose.wac

@@ -0,0 +1,15 @@
+package example:composition;
+
+let leaf = new test:leaf {
+  ... 
+};
+let middle = new test:middle {
+  to-test: leaf.to-test,
+  ...
+};
+let runner = new test:runner {
+  to-test: middle.to-test,
+  ...
+};
+
+export runner...;

tests/runtime/common-types/leaf.cpp

@@ -0,0 +1,15 @@
+#include <leaf_cpp.h>
+
+using namespace test::common::test_types;
+
+R1 exports::test::common::to_test::Wrap(F1 flag) {
+    if (flag == F1::kA) {
+        return R1{ 1, flag };
+    } else {
+        return R1{ 2, flag };
+    }
+}
+
+V1 exports::test::common::to_test::VarF(void) {
+    return V1(V1::B(42));
+}

tests/runtime/common-types/middle.cpp

@@ -0,0 +1,11 @@
+#include <middle_cpp.h>
+
+using namespace test::common::test_types;
+
+R1 exports::test::common::to_test::Wrap(F1 flag) {
+    return ::test::common::to_test::Wrap(flag);
+}
+
+V1 exports::test::common::to_test::VarF(void) {
+    return ::test::common::to_test::VarF();
+}

tests/runtime/common-types/middle.rs

@@ -0,0 +1,19 @@
+include!(env!("BINDINGS"));
+
+use crate::test::common::to_test::{F1, R1, V1};
+
+use exports::test::common::to_test;
+
+pub struct Test {}
+
+export!(Test);
+
+impl to_test::Guest for Test {
+    fn wrap(flag: F1) -> R1 {
+        crate::test::common::to_test::wrap(flag)
+    }
+
+    fn var_f() -> V1 {
+        crate::test::common::to_test::var_f()
+    }
+}

tests/runtime/common-types/runner.cpp

@@ -0,0 +1,20 @@
+#include <assert.h>
+#include <runner_cpp.h>
+
+int main() {
+    using namespace ::test::common::test_types;
+    
+    R1 res = test::common::to_test::Wrap(F1::kA);
+    assert(res.b == F1::kA);
+    assert(res.a == 1);
+
+    R1 res2 = test::common::to_test::Wrap(F1::kB);
+    assert(res2.b == F1::kB);
+    assert(res2.a == 2);
+
+    V1 res3 = test::common::to_test::VarF();
+    assert(res3.variants.index() == 1);
+    assert(std::get<1>(res3.variants).value == 42);
+
+    return 0;
+}

tests/runtime/common-types/test.wit

@@ -0,0 +1,30 @@
+//@ dependencies = ['middle', 'leaf']
+//@ wac = 'compose.wac'
+
+package test:common;
+
+interface test-types {
+    flags f1 { a, b }
+    record r1 { a: u8, b: f1 }
+    variant v1 { a, b(u8) }
+}
+
+interface to-test {
+    use test-types.{f1, r1, v1};
+
+    wrap: func(flag: f1) -> r1;
+    var-f: func() -> v1;
+}
+
+world leaf {
+    export to-test;
+}
+
+world middle {
+    import to-test;
+    export to-test;
+}
+
+world runner {
+    import to-test;
+}